[S/st 54]

Originally Posted by Aaron Quinton

Could be, likely bringing piston speed down

NHRA has no limit on bore center distance. Looks like most turbo promods are running 5.0" B/C hemis.

All of you guys do a heck of a job thinking "outside the box" with a awesome enthusiasm but don't you think it's time to make the box bigger?Or make it bigger inside the box we already have?

[Johnny406]

Just got back from camping and I sure was hoping he would've made the show. Great to see a production style Pontiac running those number, very curious/excited to see what happens next year...

[Jack Gifford]

Originally Posted by gene simmons

... if you stretch a allpontiac block to a 5" bs,it would only make the block a few inches longer...

About 1.5" longer?

[mgarblik]

One disadvantage of stretching the bore spacing inside the existing block dimension and increasing the bore to 4.400" is the removal of even more material from the main web area. Very careful machining would be needed to try and keep bulkhead material in the block. This is another area where a deep skirt billet block has a real advantage. To be optimal, race after race, a production based shallow block is a real handicap. The solid aluminum IA II block addressed the main bulkhead issue by making the bores for the sleeves stepped and very short, leaving much more material around the main web. Made it very difficult to hone for the sleeves but the effort is worth it. Making the bores 4.650" minimum for sleeves, may leave the bulkheads very thin.

[smokey 1978]

Not a bad run for a non promod pontiac engine! If someone would just sponsor him and build a pontiac promod engine he would competitive period!!!!

[Scott Roberts]

Originally Posted by smokey 1978

Not a bad run for a non promod pontiac engine! If someone would just sponsor him and build a pontiac promod engine he would competitive period!!!!

And what does a Pontiac pro mod engine look like??

[dci]

Originally Posted by Aaron Quinton

If you can package a 2.4 intake without shrouding I'm with you.

My RA5 head was designed with the opportunity to use a larger intake valve without shrouding. A 2.400 will fit with a 1.700" exhaust on a 4.400 bore and the intake valve can be as much as .230" from the cylinder wall if done correctly. Here is the math: 4.400"-Intake valve 2.400"- exhaust 1.700"- distance between valves .030"- exhaust valve distance from cylinder wall .040"= .230" I don't think for a turbo application that you will need anything bigger than a 1.700" valve to make enough HP. If you do then shrink up the intake to cylinder wall value a little and make it bigger. It can be done. I have a NASCAR RO7 cylinder head here at the shop right now that the intake valve is .210" away from the cylinder wall and the exhaust valve looks as it may even rubber the cylinder wall it's that close.

[S/st 54]

Originally Posted by Scott Roberts

And what does a Pontiac pro mod engine look like??

So far with a 6.364 looks like it would be #1or#2 maybe #3 in Top sportsman.........you know that class Curt Geise has been chasing year in and year out with his twin turbo Pontiac Powered GTO since what 2009?And Curt is pretty dang killer on the tree (by bracket racing standards)and pretty killer on a .400 tree in super gas....just tells me he knows how to stage a tt car....do it consistently....and cut down the tree......and he's been chasing it for a while now there's plenty of documentation out there that support that.

[Aaron Quinton]

Depends on what you mean Jason. If you're talking bigger bore centers then my vote would be no. You might as well run a bbc at that stage. It's way cheaper.

Originally Posted by S/st 54

All of you guys do a heck of a job thinking "outside the box" with a awesome enthusiasm but don't you think it's time to make the box bigger?Or make it bigger inside the box we already have?

[Scott Roberts]

Originally Posted by S/st 54

So far with a 6.364 looks like it would be #1or#2 maybe #3 in Top sportsman.........you know that class Curt Geise has been chasing year in and year out with his twin turbo Pontiac Powered GTO since what 2009?And Curt is pretty dang killer on the tree (by bracket racing standards)and pretty killer on a .400 tree in super gas....just tells me he knows how to stage a tt car....do it consistently....and cut down the tree......and he's been chasing it for a while now there's plenty of documentation out there that support that.

I'm confused as to how that answered my question...

[gene simmons]

Originally Posted by mgarblik

One disadvantage of stretching the bore spacing inside the existing block dimension and increasing the bore to 4.400" is the removal of even more material from the main web area. Very careful machining would be needed to try and keep bulkhead material in the block.

The outside dimension of the block would have to change,therefore,making the block a couple inches longer.Without having info or cad files,i wouldn't know how they would do it,although Robert C said they could do a 5" bs.
Out of curiosity,you could ask them.
There 4.75 bs looks like it is maxing out tolerances to achieve a wider bs. IDK

[Anderson Port Development]

Originally Posted by Scott Roberts

And what does a Pontiac pro mod engine look like??

... well, that's good question, which is not really simple to answer ...

... one of the advantages of the other brands 5.0 borespacing is they get to 526c.i. with much less stroke, therefore allowing a shorter deck block and still have enough room to put a good piston, pin, and ring pack in the engine ...

... if a Pontiac ProMod is to be considered, and if the std. 4.620 b/s is used, then obviously more stroke is required to achieve the same c.i. because of the smaller bore, so now to run an adequate piston, rod and ring pack, you now need a taller deck block because of the bigger stroke, which also makes the engine heavier to some degree, but the smaller bore will shroud the 2.400 intake valve more than the larger bored 5.0 b/s engine using the same 2.400 valve, which is not optimum either ...

... the CV-2, Visner's, or the Warp 6's would be my choices for an adequate cylinder head on this 4.620 b/s Pro Mod application, but if one is to consider increasing the Pontiac b/s to 5.0 b/s, which means a billet block and billet heads, the question Scott asked is now simple to answer at this stage, as it won't look like Pontiac at all, because no high end shop that builds NHRA Pro Mod engines is going to design a 5.0 b/s inline wedge head to go Pro Mod racing, so now what heads are left to consider for the 5.0 b/s Pontiac ?? ...

... obviously the current billet heads are going to be the easiest to adapt to the larger b/s as they can be easily changed in CAD to match 5.0 b/s, all the welding needed to do this to a 4.620 Pontiac casting would be, well, kinda not smart ...

... but the question that begs now, is after increasing b/s to 5 inches why would we not modify the cam tunnel and lifter bore configurations at the same time, we're already to the point of billet blocks and heads, so this now opens the door to a totally different cylinder head design to go hand in hand with the modern lifter bore and cam tunnel configurations, basically at this stage the "DOMINOE" effect has begun heavily and the engine becomes something radically different from where it started, and what you would find is the further one goes down the path of altered bore spacing and the changes the components go through, the more the engine will look like what the NHRA Pro Mod guys are already running ...

... the fact they call them Chevy engines is quite hilarious to me, they couldn't be further from it ...

[Scott Roberts]

You made my point exactly Bill.... Once you start making all the changes needed, its no longer a pontiac, its simply a current pro mod engine...

[mgarblik]

Originally Posted by Anderson Port Development

... but the question that begs now, is after increasing b/s to 5 inches why would we not modify the cam tunnel and lifter bore configurations at the same time, we're already to the point of billet blocks and heads, so this now opens the door to a totally different cylinder head design to go hand in hand with the modern lifter bore and cam tunnel configurations, basically at this stage the "DOMINOE" effect has begun heavily and the engine becomes something radically different from where it started, and what you would find is the further one goes down the path of altered bore spacing and the changes the components go through, the more the engine will look like what the NHRA Pro Mod guys are already running ...

... the fact they call them Chevy engines is quite hilarious to me, they couldn't be futher from it ...

EXACTLY! It is not a Chevy or anything else. It is a "Sonny's", "Alan Johnson", "BAE", or whatever. A Pontiac version would be the same, but a less developed, "whatever" engine. If it's a wedge some call it a "Chevy". If it's a hemi, they call it a "Chrysler". These people are idiots and should not be part of any serious conversation. If I was a sponsor prepared to bankroll Mr. Shearer's Pro-Mod future, I don't think I could get behind an engine development program that went this direction. I think there is a little more in his Pontiac configuration. If he really worked hard at it, went with the solid aluminum block and some good heads, he could probably run 5.90's. But he will have to work hard for it. With a current pro-mod engine, he would be there the first time out probably. His personal goals and whose money is being spent will drive the direction of his program moving forward.

[mike leech]

Originally Posted by Scott Roberts

And what does a Pontiac pro mod engine look like??

just like a real promod engine but with the word pontiac on the valve covers......

[Anderson Port Development]

Originally Posted by mike leech

just like a real promod engine but with the word pontiac on the valve covers......

... Lol, and there's the short and sweet version ...

[Johnny406]

Originally Posted by mike leech

just like a real promod engine but with the word pontiac on the valve covers......

Just like a nitro Toyota...

[S/st 54]

Originally Posted by Scott Roberts

I'm confused as to how that answered my question...

Hit the quote button instead of reply button to throw out a random thought.....my bad Scott.

[Scott Roberts]

So I guess this thread was put to rest after the past weekend...lol

[GTOGEORGE]

I think the next step is Justin chiming in.


GTO George